1. Field of the Invention
The present disclosure relates generally to a device and a system for feeding a media sheet from a stack of media sheets and, more particularly, to a device and a system for changing the position of a pick arm across a media path based on the size of media sheets in a media stack.
2. Description of the Related Art
A typical image forming apparatus such as an electrophotographic printer or an inkjet printer, for example, includes a media sheet feed system having a media picking mechanism for picking a media sheet and a media tray for holding a stack of media sheets, such as paper, on which to print images. One type of picking mechanism utilizes an auto compensating pick module (ACM). The ACM includes at least one pick roller and a gear train that transmits both a rotational force and a downward force to the pick roller.
In reference edge type systems, the ACM is typically positioned to feed a wide range of media sizes without requiring adjustments. For example, the ACM may be positioned across the media feed direction such that there are always two pick roller tires touching any supported media from the narrowest to the widest. If two tires are not placed on a supported media, misfeeds and paper jams may result during a sheet pick operation.
However, when the ACM is positioned to allow feeding of a narrowest supported media, pick reliability of a widest supported media is compromised. This is because the ACM is positioned offset from the centerline of the widest supported media in order to support the narrowest supported media. When pick forces are applied to a wide media sheet, the offset location of the pick forces creates a moment on the media sheet that skews the media when picked by the at least one pick roller. The skew in the media must then be removed by a downstream media alignment system before image transfer. Skewing the media during a pick operation further creates an opportunity for paper jams and increases the amount of energy that must be used on the media sheet by the alignment system.
Based upon the foregoing, there is a need to effectively reduce pick skew and improve reliability of a picking mechanism in reference edge type systems by substantially eliminating the moment placed on the sheet by the pick roller tires during a media sheet picking operation. Further, there is also a need to increase the number of different media sizes supported by a media tray in an image forming apparatus without compromising pick reliability of the widest supported media.